Did you find your ancestor's arrival manifest? How about his SS-5Form? Have you considered requesting it?
Would Samuel's State Marriage Record to Ida DOVNARSKY have his place of birth or at least parents names?
Could Ida and Sam have been from same location? Do you know Ida's place of birth? I found DOWNARSKIs arriving NY Ellis Island from Grajewo, gubernia Lomza.
7:15 a.m. March 26, 2019
You have a WW 2 Draft Registration Form for your Sam MILLER but the wife's name is Annie. The birth year and a month is different. Sam was supposedly born in Warsaw . There was also a gubernia named Warschau [Warszawa] as well as a city.
Which birth date is correct. Is it March 15, 1888 or Sept. 15, 1889 ?
Did his Intention not come with Petition?
The 1920 census has Sam arriving in 1903 and being naturalized 1913.
1930 census has Sam arriving in 1906 and is Na-naturalized.
To me, the signatures are different on his WW 1, WW 2 and Intention. Sort of like not the same person signing it. Do you have Sam's Death Certificate? It might have his social security numbers. I can think of only that form to confirm the birth date, place of birth and parents names. I'm not finding Sam /Samuel MILLER using "range" 1888 to 1889 in Social Security Death Index.